1. Field of the Invention
The present invention relates to an electrode for an electro-optical device.
The present invention further relates to an electro-optical device provided with such an electrode.
The present invention further relates to a method of manufacturing such an electrode.
The present invention further relates to a method of manufacturing an electro-optical device provided with such an electrode.
The present invention further relates to a device for manufacturing such an electrode.
The present invention further relates to an apparatus for manufacturing an electro-optical device provided with such an electrode.
2. Related Art
An electro-optical device is a device that provides for an optical effect in response to an electric signal, or that generates an electric signal in response to an optical stimulus. Examples of the first are light emitting diodes, such as organic light emitting diodes and electro chromic devices. Examples of the second are photo voltaic cells.
For large area OLED lighting on flexible plastic substrates, a large current is required to drive the system. The present thin film materials used for the anode (e.g. ITO) and cathode (e.g. Ba/Al) have a large resistivity and the large currents give rise to substantial voltage drop, which determine a non-uniform light emission. For producing large area flexible OLED devices on plastic substrates there is a need for an additional metallization structure to support one or both electrodes. For reducing the manufacturing costs, such structured metallization coatings will preferably be applied on rolls of plastic foil using an inline roll-to-roll web coating process.
Accordingly, for electro-optical devices, such as light emitting devices and electro-chromic devices, but also for photo-voltaic products there is a need for a metallization structure that on the one hand has a good electrical conductivity, while on the other hand has a high transmission for photon radiation.
An electrode for an electro-optical device is disclosed in US-patent application 2002130605A. Light is enabled to pass through this electrode which comprises a pattern of conductive elements. The elements have dimensions small compared to the wavelength of light, so that the electrode appears transparent. The light intensity distribution after having penetrated the electrode compared with the light intensity distribution before having penetrated the electrode is influenced by forward scattering.
It is not described in the cited US-patent application how the electrode is connected to an external power line. Usually this is realized by a bus-bar which is connected to the edges of the electrode. However, the bus-bar should be applied before the final product using the electrode is completed. Accordingly, the dimensions of the bus-bar should be known in advance. It is desired to provide an electrode and an electro-optical product provided with such an electrode that can be manufactured in arbitrary dimensions.